jfusco20 wrote:I am getting right around 14.3 city/highway! The truck has about 1,100 miles on it. I was thinking of doing a CAI, a throttle body spacer, a mass air, exhaust and a tuner! Just wondering if anyone has these add ons and is getting better gas mileage? What kind of HP gains are you seeing?? I was wondering if I should be running my truck on 87 octane or 93 octane? Also does the MPG's get better as engine breaks in?

do not get a tb spacer.. waste, won't gain you anything... and especially do NOT get an aftermarket MAF sensor! they screw your fueling... they fool the ecm into thinking your running leaner than you really are, and when you go to get tuned, you won't be able to get the fueling dialed in correctly, because it will never be correct due to the aftermarket MAF sensor reporting false information anyway...

the stock GM MAF's are good for 550/600+ hp anyway... no need to change it at all...

Checked my mileage this past weekend on a trip that included city, highway, interstate, and road construction traffic.... Started with ~ 350 miles on truck (2012 crew cab with Max Trailering Pack). First tank almost all interstate: 16.0 Second tank was a mixture of interstate, city, and tied up in road construction area: 14.1 Third tank mostly highway and interstate: 16.9

I've been hovering right around there as well. I'm just above 50K miles. Between the 2500 6.0 and 1500 6.2 max trailer package? I've owned both and will stick with the 6.2. Much better gas mileage and way more HP. The only thing I don't have is the spring capacity for the bed haul. It will tow with no problem!!!!!

Checked my mileage again this past weekend while towing a 6' X 10' enclosed trailer. A bit over 200 miles each direction - almost all interstate. Running 76 mph - 77 mph into a headwind going I got 8.7 mpg. Coming back I drove 74 mph - 75 mph and had a slight tail wind. Got 9.8 mpg. Not good at all considering how little weight I was hauling. Going to be "interesting" to see what I get when I tie onto my 7' X 16' enclosed trailer....

David_L6 wrote:Checked my mileage again this past weekend while towing a 6' X 10' enclosed trailer. A bit over 200 miles each direction - almost all interstate. Running 76 mph - 77 mph into a headwind going I got 8.7 mpg. Coming back I drove 74 mph - 75 mph and had a slight tail wind. Got 9.8 mpg. Not good at all considering how little weight I was hauling. Going to be "interesting" to see what I get when I tie onto my 7' X 16' enclosed trailer....

I usually get 12-14 towing my 5th wheel in the mountains. Roughly 7000 LB.

I'm new here so thanks for having me around. I have a 2012 Denali that I just bought about a week ago and just took her on a 3500 km road trip, actually I am about 2000 km into right. Ow as I am typing. I'm not driving and tyPing but anyway.... On my dic I was quit surprised to see that I was getting 17.8 mpg through the rocky mountains so far the whole trip has been mountains, and the rest will be mountains as well. I have driven through the mountains plenty of times an know how to get good mileage. Run the piss out of every hill.

I am a owner of a 2005 Duramax that I have taken threw the mountains and was able to get 23 mpg hand calculated. So to see a gas get as good as 17 I was quit impressed. And I am pretty heavy threw towns on that throttle cause ******** does that 6.2 sound good. Anyways I am here on the forum and thank everyone in advance for the help in the future. I have been on forums with my Duramax for over 6 years and have received tons of help. So I am looking forward to sharing experiences and knowledge with all of you guys.